The present invention relates to a brake arrangement, especially to a disk brake for vehicles with brake pads guided in a brake caliper on both sides of a brake disk which are operatively connected with hydraulically actuatable actuating pistons, whereby each actuating piston includes a bore facing the brake pad in which is arranged an insert member.
Disk brakes can tend to squeak during the braking operation which is caused essentially by an oscillating movement of the brake caliper as well as of the brake pads. Vibrations can occur as a result of these movements at the brake arrangement which radiate a sound that is noticeable to the human ear as so-called "squeaking."
The present invention is concerned with the task to suppress a brake squeaking during a brake actuation.
The underlying problems are solved according to the present invention in that the insert member covering the piston surface and retained with play relative to the inner circumferential and bottom surfaces of the bore consists of a plate-shaped intermediate inset member that is connected with the two insert members.
An embodiment is already described in the German application No. P 37 38 764.2, filed in Germany on Nov. 14, 1987 corresponding to the U.S. patent application No. 270,689,filed Nov. 14, 1988, in which a metallic insert member having substantial mass is retained with play in the hollow actuating piston by way of a flange element on the end surface of the actuating piston. A structurally simple part is achieved thereby which can be inserted into a bore of the actuating piston and suppresses a brake squeaking by a vibration reduction and damping. This damping takes place essentially by a frictional connection between the flange of the insert member and the piston as well a between the flange of the insert member and the back surface of the brake pad.
It has been found in operation that the brake pad carries out movements in the circumferential-, radial- and axial-directions. In order that these movements can be prevented as far-reachingly as possible, because they also excite the brake caliper into vibrations, a plate-shaped intermediate inset member abutting areally at the brake pad is utilized in lieu of a plate-shaped part at the insert member according to the aforementioned German application, which intermediate member is rigidly connected with the two insert members. A movement-impeding action on the brake pad and therewith also on the brake caliper is achieved by this plate-shaped intermediate member having a friction-increasing coating, which extends nearly over the entire back surface of the brake pad and is connected with the insert members. Especially coatings consisting of rubber material contribute thereto, as a result of which a deliberate damping of the circumferential-friction vibrations of the brake pads is achieved and the brake pad noises can be suppressed. In particular a rubber-like layer or a lacquer (paint) layer is arranged on the surface facing the brake pad for the purpose of increasing the friction between the intermediate inset member and the brake pad.